1. Technical Field
The present disclosure relates to a nonaqueous electrolyte secondary battery, more specifically, to a lithium on secondary battery.
2. Description of the Related Art
In nonaqueous electrolyte secondary batteries, phosphorus-containing compounds are known as flame retardants inhibiting exothermic reaction between positive electrode active materials and electrolytic solutions being liquid nonaqueous electrolytes. Japanese Patent No. 3131905 discloses inhibition of the exothermic reaction between a positive electrode active material and an electrolytic solution by dissolving a phosphate ester in the electrolytic solution in an amount of 15% by mass or more based on the total amount of the electrolytic solution.